Paving of a roadway with asphalt paving material is generally carried out by a paving machine that is supplied with asphalt paving material by a number of supply trucks and/or a material transfer vehicle. The paving machine is self-propelled and driven by a wheeled or tracked drive system. In a common type of paving machine, an asphalt receiving hopper is located at the front end of the machine to receive asphalt paving material from a truck or material transfer vehicle, and a hopper conveyor located below and/or behind the asphalt receiving hopper transfers the asphalt paving material from the hopper to a transverse distributing auger that is mounted near the rear of the machine. The asphalt paving material is deposited onto and across the roadway or other surface to be paved by the distributing auger. A floating screed located at the rear end of the machine behind the distributing auger compacts the asphalt paving material to form an asphalt mat.
Asphalt paving material is comprised of an asphaltic binder and aggregates of various particle sizes, including both coarse and fine aggregate materials. Because the equipment needed to produce asphalt paving material is expensive and the space required extensive, asphalt paving material is typically produced in a production facility that is dedicated to such purpose. Consequently, it is frequently necessary to transport the asphalt paving material from its place of origin to an asphalt paving machine at a remote paving site. The asphalt paving material is transported in dump trucks to an asphalt paving machine or to a material transfer vehicle that completes the transfer to the asphalt paving machine. Sometimes, asphalt paving material is discharged directly from the transport dump trucks into the asphalt receiving hopper of the asphalt paving machine. On other occasions, however, material transfer vehicles are used to shuttle asphalt paving material between the supply trucks and the asphalt paving machine.
A self-propelled material transfer vehicle typically includes a large-capacity truck-receiving hopper and an inclined truck-unloading conveyor extending upwardly from this hopper. Asphalt paving material carried by the truck-unloading conveyor from the truck-receiving hopper is discharged off the elevated output end of the truck-unloading conveyor into a chute mounted on the lower end of a paver-loading conveyor, or into an intermediate surge bin that is sized to hold the entire load of a delivery truck. The discharge of asphalt paving material off the elevated output end of the truck-unloading conveyor so that it may fall under the influence of gravity into a chute or surge bin assists in preventing undesirable segregation of the various particulate components of the asphalt paving material by particle size. Material transfer vehicles of the type that are equipped with a surge bin typically include a conveyor in the surge bin that is adapted to transfer the asphalt paving material to a paver-loading conveyor. Paver-loading conveyors mounted on material transfer vehicles with and without surge bins are generally pivotable about an essentially vertical axis so that the transfer vehicle can be positioned alongside an asphalt paving machine that is laying an asphalt mat and rapidly discharge asphalt paving material into the hopper of the paving machine as the material transfer vehicle moves with the paving machine along the roadway. Because of its rapid loading and unloading capabilities, a material transfer vehicle can rapidly shuttle between delivery trucks at a pick-up point and an asphalt paving machine that is laying an asphalt mat at a paving site so that there is less likelihood that the paving machine will have to stop paving because of a lack of asphalt paving material.
Regardless of how the asphalt paving material is delivered to the asphalt paving machine, the rate of delivery of asphalt paving material to the paving machine may vary during a paving operation, depending on the production rate at the asphalt production facility, the demand for asphalt paving material produced by such facility, traffic conditions encountered by the delivery vehicles and conditions at the paving site, among other variables. Consequently, it is sometimes necessary for the asphalt paving machine to wait on the delivery of asphalt paving materials. Starting and stopping an asphalt paving machine during a paving operation can cause variations in the surface of the roadway being paved. Therefore, it generally advantageous to control the paving operation to insure a consistent flow of asphalt paving material through the paving machine as the paving process is carried out. A paving machine operator may focus on controlling the rate of advance of the asphalt paving machine across the roadway and on steering the machine during the paving operation. However, it would also be desirable if a method and system could be provided that could control the rate of deposition of asphalt paving material on the roadway by the distributing auger.